BMP and Notch crosstalk in cerebral arteriovenous malformations

摘要 血管疾病的治疗进展可能具有深远的公共利益。骨形态发生 骨形成蛋白（BMPs）和Notch信号传导正在成为血管系统的重要调节因子，并且在 例如动静脉畸形（AVM）。我们之前的研究表明， BMP诱导Notch信号传导导致脑AVM。在初步研究中，我们证明了一个强大的 人脑AVM中Sox 2的内皮诱导，以及 限制EC中的Sox 2。我们发现Sox 2的过度转录活性破坏了脑EC分化， 导致AVM管腔紊乱。Sox2受BMP和Notch信号传导的串扰调节。在体外，我们发现 BMP诱导的Notch配体Jagged 1和2上调Sox 2， 减少Sox 2诱导。在体内，Jagged 1和2以及Notch1在小鼠中增加并直接靶向Sox 2。 MGP缺陷的脑EC，其中Jagged 1或2的减少减少Sox 2表达。相反，我们 发现Sox 2在肺AVM中的转录作用没有诱导或显著变化，相反， VEGF表达增加。限制内皮Sox2不能改善肺AVM。诱导 Sox 2，Notch需要Ski相互作用蛋白（Skip），该蛋白在脑EC中有活性，但在肺EC中无活性。 此外，我们还创建了一个高通量筛选模型，旨在识别化合物 抑制脑内皮细胞Sox 2表达。我们推测Sox 2及其转录调控可能与Sox基因的转录调控有关。 活性在正常脑组织EC分化和管腔形成的维持中是重要的 脉管系统特异性目的1将确定Sox2如何受BMP和Notch信号转导的调节，并影响BMP和Notch的表达。 脑内皮细胞的分化。具体目标2将确定Sox 2是否被诱导有助于人类 脑动静脉畸形具体目标3将确定Sox 2的调节在脑与肺中的差异 AVM和识别抑制Sox2表达的化合物。如果成功，则获得 这些信息可以转化为使用Sox 2抑制剂治疗脑AVM的策略。研究 还可能提供AVM组织特异性形成的重要见解，并导致不同的治疗 反车辆地雷战略。

ABSTRACT Therapeutic advances in vascular disease may have far-reaching public benefits. Bone morphogenetic proteins (BMPs) and Notch signaling are emerging as essential regulators of the vasculature, and important in disorders such as arteriovenous malformations (AVMs). Our previous studies have demonstrated that excess BMP induces Notch signaling causing cerebral AVMs. In preliminary studies, we demonstrate a strong endothelial induction of Sox2 in human cerebral AVMs, and a dramatic improvement of cerebral AVMs after limiting Sox2 in ECs. We find that excess transcriptional activity of Sox2 disrupts cerebral EC differentiation to cause lumen disorder in AVMs. Sox2 is regulated by crosstalk of BMP and Notch signaling. In vitro, we show that BMP-induced Notch ligands Jagged 1 and 2 upregulate Sox2, and knockdown of Notch1 receptor diminishes Sox2 induction. In vivo, Jagged 1 and 2 and Notch1 are increased and directly targeted Sox2 in MGP-deficient cerebral ECs, in which a decrease of Jagged 1 or 2 reduces Sox2 expression. In contrast, we find no induction or significant changes of transcriptional effects of Sox2 in pulmonary AVMs, where instead the expression of VEGF is increased. Limiting endothelial Sox2 does not improve pulmonary AVMs. To induce Sox2, Notch requires ski-interacting protein (Skip), which is active in brain ECs but inactive in pulmonary ECs. Furthermore, we have created a high throughput-screening model and aim to identify chemical compounds that suppress Sox2 expression in brain ECs. We hypothesize that regulation of Sox2 and its transcriptional activity is important in the maintenance of EC differentiation and lumen formation in normal cerebral vasculature. Specific Aim 1 will determine how Sox2 is regulated by BMP and Notch signaling and affects the differentiation of brain endothelial cells. Specific Aim 2 will determine if Sox2 is induced to contribute to human cerebral AVMs. Specific Aim 3 will determine how regulation of Sox2 differs in cerebral versus pulmonary AVMs and identify the chemical compounds that suppress Sox2 expression. If successful, the obtained information may translate into strategies for using Sox2 inhibitors in the treatment of cerebral AVMs. The study may also provide significant insights of tissue-specific formation of AVMs, and lead to different treatment strategies for AVMs.